Input clutch assembly for infinitely variable transmission

ABSTRACT

The present invention provides an infinitely variable transmission for a powered vehicle which includes a power source. The transmission includes an input shaft and an output shaft, the output shaft being spaced from the input shaft. The transmission further includes a variator coupled between the input shaft and output shaft. In addition, at least two planetary gearsets are disposed adjacent to the variator and an input coupler is configured to selectively couple the variator to the power source.

RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 13/959,163, filed Aug. 5, 2013, which is a divisionalapplication of U.S. patent application Ser. No. 13/228,632, filed Sep.9, 2011, issued as U.S. Pat. No. 9,109,663, which claims priority toU.S. Provisional Patent Application Ser. No. 61/413,530, filed Nov. 15,2010, all of which are hereby incorporated by reference in theirentireties.

FIELD OF THE INVENTION

The present invention relates to a transmission for a powered vehicle,and in particular to a multi-axis gearing configuration and inputcoupler for a transmission that includes a variator.

BACKGROUND

A transmission is an apparatus through which power and torque can betransmitted from a vehicle's power unit to a load-bearing device such asa drive axis. Conventional transmissions include a variety of gears,shafts, and clutches that transmit torque through the transmission atfinite, stepped gear ratios.

A continuously variable transmission is a different type of transmissionthat can include an infinite number of gear ratios. The arrangement ofgears and the like of a continuously variable transmission can improvethe fuel efficiency of the vehicle by enabling the power unit to operateat its most efficient revolutions per minute (RPM) for a range ofvehicle speeds.

A continuously variable transmission can have multiple operating modessuch that each operating mode covers a portion of the overall ratiospread of the transmission. Each operating mode is selectable, e.g., bya clutch that is engaged by the application of hydraulic fluid pressureas commanded by the transmission's control unit. Some continuouslyvariable transmissions have a “geared neutral” mode, in which thecontinuous variation of ratio passes through the geared neutral mode intransitioning from a reverse ratio to a forward ratio. In the gearedneutral position, the vehicle's speed is zero, independently of therotational output speed by the vehicle's drive unit. Transmissions thathave a geared neutral mode may be referred to as infinitely variabletransmissions.

Like the continuously variable transmission, an infinitely variabletransmission can advantageously improve a vehicle's fuel efficiency,reduce emissions, and provide enhanced control. Infinitely variabletransmissions can be included in applications such as tractors,snowmobiles, heavy off-highway construction, mining equipment, andmarine applications. However, there are physical limitations withconventional infinitely variable transmissions that restrict someon-highway applications such as buses. Many conventional infinitelyvariable transmissions have gearing configurations that cause thetransmission to be too long, for example, to fit within a spacepositioned near the rear end of a bus. Infinitely variable transmissionstherefore have had limited penetration in the on-highway market.

In addition, an infinitely variable transmission can include a variatorassembly for transferring torque therethrough. The variator assembly isdesigned to rotate in a single direction. In some aspects, an infinitelyvariable transmission can be coupled to a diesel engine. The output of adiesel engine provides input torque to the transmission by rotating aninput shaft, torque converter, or other transmission input device.Diesel engines are known to suddenly kick back, or rotate, in adirection opposite from its normal operating direction during engineshutdown. Since the variator assembly can only rotate in one direction,the sudden kick back can cause mechanical damage to the variatorassembly. To avoid this condition and protect the variator assembly,conventional infinitely variable transmissions include a one-way clutchconnected to ground. Thus, as the engine begins to turn backwards, theclutch prevents this energy from being transferred to the transmission.Instead, the inertia is returned to the engine.

The problem with the one-way clutch setup is that the inertia returnedto the engine can damage or impact the performance of the engine. Also,at start-up, there is concern about potential torsional vibrationsaffecting the transmission.

Thus, a need exists for a gearing configuration of a variator-inclusivetransmission that reduces the overall transmission length and can beoperably coupled to a powered vehicle. Further, there is a need toreduce torsional vibrations during start-up and reduce the amount ofinertia returned to the engine during shutdown.

SUMMARY

In one exemplary embodiment of the present disclosure, an infinitelyvariable transmission is provided for a powered vehicle. Thetransmission includes an input shaft disposed along a first axis and anoutput shaft spaced from the input shaft and disposed along a secondaxis. A variator is coupled between the input shaft and output shaft.The variator is disposed along a third axis. The transmission alsoincludes at least two planetary gearsets disposed adjacent to thevariator. The planetary gearsets are disposed along a fourth axis. Thefirst, second, third, and fourth axes are parallel to one another andthe first axis and the second axis are not coaxial.

In one form of the transmission, the second axis is substantiallyvertically spaced from the first axis. In another form thereof, thefirst, second, and third axes are not coaxial. Alternatively, the thirdaxis and the fourth axis are not coaxial. The transmission can alsoinclude an input flange for coupling to a drive unit of the vehicle. Inone embodiment, the greatest distance between the input flange and theoutput shaft is less than 1000 millimeters. In another embodiment, thegreatest distance is less than about 780 millimeters. Also, thetransmission has no more than three clutch assemblies.

In a different embodiment, an infinitely variable transmission havingthree operating modes includes an input shaft and an output shaft spacedfrom the input shaft. The infinitely variable transmission furtherincludes a variator coupled between the input shaft and output shaft anda plurality of planetary gearsets disposed adjacent to the variator. Theinfinitely variable transmission also includes a first clutch assembly,a second clutch assembly, and a third clutch assembly. The first clutchassembly is engageable in a first mode, the second clutch assembly isengageable in a second mode, and the third clutch assembly is engageablein a third mode. In the first mode, the infinitely variable transmissionis operable in a reverse, a gear neutral, and a first forward mode. Inthe second mode, the transmission is operable in a second forward mode.Also, in the third mode, the transmission is operable in a third forwardmode.

In a first embodiment, the input shaft is disposed along a first axisand the output shaft is disposed along a second axis. The first axis andthe second axis are parallel to one another and not coaxial. In a secondembodiment, the variator is disposed along a third axis and theplurality of planetary gearsets is disposed along a fourth axis. In thisembodiment, the first, second, third, and fourth axes are parallel toone another. In addition, the third and fourth axes are not coaxial.

In another embodiment, an infinitely variable transmission for a vehiclehaving a drive unit includes an input shaft and an output shaft spacedfrom the input shaft. A variator is coupled between the input shaft andoutput shaft and a plurality of planetary gearsets are disposed adjacentto the variator. Also, the infinitely variable transmission includes aninput flange for coupling to the drive unit. The distance between thefront edge of the input flange and the rear edge of the output shaft isless than 1000 millimeters. Further, the distance can be less than about780 millimeters.

In one form of this embodiment, the infinitely variable transmissionincludes a first clutch assembly, a second clutch assembly, and a thirdclutch assembly. In another form thereof, the infinitely variabletransmission includes a plurality of gearsets coupled between the inputshaft and the output shaft. At least two of the plurality of gearsetsincludes a chain and sprocket assembly.

In a further exemplary embodiment of the present disclosure, aninfinitely variable transmission is provided for a powered vehicle inwhich the powered vehicle includes a power source. The transmissionincludes an input shaft and an output shaft spaced from the input shaft.A variator is coupled between the input shaft and output shaft. Theinfinitely variable transmission also includes at least two planetarygearsets disposed adjacent to the variator and an input couplerconfigured to selectively couple the variator to the power source.

In various aspects of this embodiment, the input coupler may comprise adry clutch, a damper, a stand alone clutch, a sprag or roller clutch orany combination thereof. In one form of the present disclosure, theinput coupler can be coupled to the input shaft. In another formthereof, the input coupler is not coupled to ground. In addition, thevariator can include an input and an output such that the input coupleris coupled to the input of the variator.

In a different aspect, the infinitely variable transmission can beconfigured such that the input shaft is disposed along a first axis, theoutput shaft is disposed along a second axis, the variator is disposedalong a third axis, and the at least two planetary gearsets are disposedalong a fourth axis. In this aspect, the first, second, third, andfourth axes are parallel to one another and the first axis and thesecond axis are not coaxial. The input coupler can be disposed along thefirst axis or third axis.

In an ancillary embodiment of the present disclosure, a method isprovided for selectively transferring energy from a power source to aninfinitely variable transmission. The transmission includes an inputshaft spaced from an output shaft, a variator coupled between the inputshaft and output shaft, at least two planetary gearsets disposedadjacent to the variator, and an input coupler disposed between thepower source and variator. The method includes rotating the power sourcein an input direction and transmitting energy from the power source tothe input shaft. The input coupler can be engaged and energy isselectively transferred from the power source to the transmission.

In one aspect of this embodiment, the engaging step comprises engaging aclutch or a damper. Further, the variator is selectively coupled to thepower source. In addition, the input shaft can be selectively coupled tothe power source.

In a different embodiment, an infinitely variable transmission ispowered by a power source of a vehicle. The infinitely variabletransmission has three operating modes and can include an input shaftand an output shaft spaced from the input shaft. The infinitely variabletransmission further includes a variator coupled between the input shaftand output shaft and an input coupler configured to selectively transferpower from the power source to the variator. In addition, a planetarygearset is disposed adjacent to the variator. The infinitely variabletransmission also includes a first clutch assembly, a second clutchassembly, and a third clutch assembly. The first clutch assembly isengageable in a first mode, the second clutch assembly is engageable ina second mode, and the third clutch assembly is engageable in a thirdmode. In the first mode, the infinitely variable transmission isoperable in a reverse, a gear neutral, and a first forward mode. In thesecond mode, the transmission is operable in a second forward mode.Also, in the third mode, the transmission is operable in a third forwardmode.

In the second mode, the transmission is operable in a second forwardmode. In the third mode, the transmission is operable in a third forwardmode. In one aspect of this embodiment, the input shaft is disposedalong a first axis and the output shaft is disposed along a second axis.The first axis and the second axis can be parallel to one another, andin another embodiment the two axes are not coaxial.

The variator can be disposed along a third axis and the planetarygearset can be disposed along a fourth axis. In this embodiment, thefirst, second, third, and fourth axes can be parallel to one another. Inaddition, the third and fourth axes are not coaxial.

In a further embodiment, the input coupler is disposed along the firstaxis or third axis. The input coupler can be a dry clutch, a damper, astand alone clutch, a sprag or roller clutch or any combination thereof.In addition, the input coupler can be coupled to the input shaft. Inanother aspect, the variator can include an input and an output suchthat the input coupler is coupled to the input of the variator.

An advantage associated with one aspect of the present disclosure is thecompact packaging of the internal components of an infinitely variabletransmission. The transmission can operate with only three clutchassemblies and with an input shaft and output shaft disposed alongdifferent axes or centerlines. A variator assembly can also beconfigured on a different centerline from the input shaft and outputshaft. The compact arrangement of internal components can reduce theoverall length of the infinitely variable transmission, thereby allowingit to be used in a rear-end bus application.

Another advantage of the present disclosure is the inclusion of theinput coupler to the transmission. The input coupler can protect thevariator if the power source (e.g., engine) suddenly rotates in reverseduring shutdown. During operation, the input coupler can selectively beengaged to transfer power to the variator, or if the power sourcerotates in reverse, the input coupler can be selectively disengaged. Theinput coupler can provide a direct coupling between the power source andtransmission. In addition, during startup of the vehicle, the inputcoupler can reduce torsional vibrations and therefore provides for anormal startup similar to manual and automatic transmissions.

An additional advantage associated with one aspect of the presentdisclosure is the compact packaging of the internal components of aninfinitely variable transmission. The transmission can operate with onlythree clutch assemblies and with an input shaft and output shaftdisposed along different axes or centerlines. A variator assembly canalso be configured on a different centerline from the input shaft andoutput shaft. The compact arrangement of internal components can reducethe overall length of the infinitely variable transmission, therebyallowing it to be used in a rear-end bus application.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned aspects of the present invention and the manner ofobtaining them will become more apparent and the invention itself willbe better understood by reference to the following description of theembodiments of the invention, taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1A is a schematic view of a gear configuration for an infinitelyvariable transmission;

FIG. 1B is a layout diagram of the gear configuration of FIG. 1A;

FIG. 2A is a schematic view of a gear configuration for an infinitelyvariable transmission;

FIG. 2B is a layout diagram of the gear configuration of FIG. 1A;

FIG. 3A is a schematic view of a gear configuration for an infinitelyvariable transmission;

FIG. 3B is a layout diagram of the gear configuration of FIG. 1A;

FIG. 4A is a schematic view of a gear configuration for an infinitelyvariable transmission;

FIG. 4B is a layout diagram of the gear configuration of FIG. 1A;

FIG. 5 is a front view of a plurality of axes for a gearing arrangementof the transmission of FIG. 1A;

FIG. 6 is a schematic front view of a gearing arrangement of FIG. 5;

FIG. 7A is a schematic view of a gear configuration including an inputcoupler for an infinitely variable transmission;

FIG. 7B is a layout diagram of the gear configuration of FIG. 7A;

FIG. 8A is a schematic view of a gear configuration including an inputcoupler for an infinitely variable transmission; and

FIG. 8B is a layout diagram of the gear configuration of FIG. 8A.

Corresponding reference numerals are used to indicate correspondingparts throughout the several views.

DETAILED DESCRIPTION

The embodiments of the present invention described below are notintended to be exhaustive or to limit the invention to the precise formsdisclosed in the following detailed description. Rather, the embodimentsare chosen and described so that others skilled in the art mayappreciate and understand the principles and practices of the presentinvention. For example, while certain aspects of the disclosure arediscussed herein in the context of an infinitely variable transmission,it will be understood by those skilled in the art that aspects of thepresent disclosure are applicable to other types and configurations ofvehicle transmissions.

This disclosure describes several gear schemes that provide multipleoperating modes for an infinitely variable transmission. This disclosurealso illustrates and describes a number of gearset and clutcharrangements that may be used to implement the illustrated gear schemes.For purposes of the present disclosure, a gearset is used to describe anarrangement of gears and/or chain and sprocket assembly. For example, agearset may include a pair of meshing gears or at least two gears and adirectional idler gear disposed therebetween. Alternatively, a gearsetmay include a pair of sprockets that are coupled by a chain. In anotherform thereof, a gearset may include a planetary gearset. A planetarygearset can include a ring gear, a sun gear, and a plurality of piniongears. One skilled in the art will appreciate other possible definitionsof a gearset based on the different embodiments described in thisdisclosure.

An exemplary embodiment of a gear configuration 1000 for an infinitelyvariable transmission is shown in FIG. 1A. The layout 1100 of the gearconfiguration 1000 is illustrated in FIG. 1B. In this embodiment, thetransmission gearing is driven by a rotating input shaft 100, and theoutput of the transmission is transferred to the vehicle load by arotating output shaft 126. In FIG. 1B, the input shaft 100 is shown asbeing on a first axis 176 and the output shaft is disposed on a secondaxis 184. In one aspect, the first axis 176 and second axis 184 can beparallel and coaxial. In another aspect, however, the first axis 176 andsecond axis 184 are parallel but not coaxial. For purposes of thisdisclosure, the term “axis” can also be referred to as a “centerline”and both terms are interchangeable.

A drive unit (not shown) drives the rotation of the input shaft 100. Thedrive unit can include an internal combustion engine, such as aspark-ignited or compression-ignition type (i.e. diesel) engine, anengine-electric motor combination, or other suitable source ofrotational power. The transmission can be coupled to the drive unit byan input flange 180. The input flange 180 is disposed near the front endof the transmission opposite the output shaft 126. The vehicle load canbe, for example, the vehicle's drive wheels, an auxiliary gearbox (e.g.a transfer case or drop box), or a power take-off device, such as apump, mixer, lifter, shoveler, compressor, compactor, or blower, as canbe provided with commercial vehicles such as trucks or buses.

The length of the infinitely variable transmission can be measured fromthe input flange to the output shaft. In FIG. 1B, for example, thelength is measured from the front edge of the input flange 180 to therear edge 182 of the output shaft 126. In a conventional infinitelyvariable transmission, the length of the transmission is about 39.96inches (1015 millimeters). In one embodiment of the present invention,the length of the infinitely variable transmission is less than 39inches (990 millimeters). In another embodiment, the length is less than35 inches (889 millimeters). In a different embodiment, the length isless than 30.7 inches (780 millimeters). With the input shaft 100 andoutput shaft 126 being disposed on different axes, the length of theinfinitely variable transmission can advantageously be reduced.

In the embodiment of FIG. 1A, the gear configuration 1000 of theinfinitely variable transmission includes a plurality of gearsets, aplurality of clutch assemblies, and a variator assembly 114 coupledbetween the input shaft 100 and output shaft 126. The plurality ofgearsets includes input gearsets 102, 110, 112 and output gearsets 122,124. The plurality of clutch assemblies includes C1, C2, and C3. Inputgearsets 110 and 112 can include a pair of gears (with an idler disposedtherebetween), for example, or a chain and sprocket assembly. Outputgearsets 122 and 124 can also include meshing gears, as will bedescribed in further detail below.

The variator assembly 114 can be a toroidal variator, such as a fulltoroidal traction drive-type variator manufactured by TorotrakDevelopment, Ltd. of Lancashire, United Kingdom. However, other types ofvariator assemblies can be used to provide a continuous variation oftransmission ratio.

With reference to the embodiment of FIG. 1B, the variator assembly 114has a pair of input discs 156, 158 and a pair of output discs 160, 162.The input discs 156, 158 are coupled to a variator input shaft 116. Theoutput discs 160, 162 are coupled to a variator output shaft 118. Thespace between the inner surfaces of the input discs 156, 158 and theinner surfaces of the corresponding output discs 160, 162 form a hollowdoughnut shape or ‘toroid.’ A number of rollers (not shown) are locatedinside the toroidal space defined by the inner surfaces of the discs156, 158, 160, 162. The rollers transmit torque from the input discs156, 158 to the output discs 160, 162 via a traction fluid (not shown).

Variator torque is controlled by a hydraulic circuit (not shown), whichincludes hydraulic actuators (e.g., pistons and lever assemblies) thatapply an adjustable force to the rollers. The force applied by ahydraulic actuator to a roller is balanced by a reaction force resultingfrom the torques transmitted between the surfaces of the variator discsand the rollers. The end result is that in use, each roller continuouslymoves to locations and tilt angles required to transmit a torquedetermined by the force applied by the hydraulic actuators. A differencein the forces applied to the rollers changes the rollers' tilt angle,thereby establishing the variator ratio. A change in the rollers' tiltangle can result not only in a net torque at the transmission output butalso in a change in torque direction. The direction of the torque outputdetermines whether the torque application is positive or negative.

In the embodiment of FIGS. 1A and 1B, the infinitely variabletransmission can also include a first planetary gearset 104 and a secondplanetary gearset 120. The first planetary gearset 104 includes a firstring gear 138 (FIG. 1B), a first carrier assembly 140 (FIG. 1B), and afirst sun gear 142 (FIG. 1B). Similarly, the second planetary gearset120 includes a second ring gear 144 (FIG. 1B), a second carrier assembly146 (FIG. 1B), and a second sun gear 148 (FIG. 1B). As shown in FIG. 1B,the first planetary gearset 104 and second planetary gearset 120 arearranged beside, rather than in front of or behind, the variatorassembly 114, thereby shortening the overall length of the transmission.

In FIG. 1B, the variator assembly 114 is positioned on a third axis orcenterline 174 and the first planetary gearset 104 and second planetarygearset 120 are positioned on a fourth axis or centerline 178. In thisembodiment, the third axis 174 and fourth axis 178 are parallel to oneanother, but the axes are not coaxial. Further, in one embodiment, thefirst axis 176, second axis 184, third axis 174, and fourth axis 184 areparallel to one another but not coaxial. In another embodiment, the axescan be parallel and disposed in the same plane. Alternatively, the axescan be parallel to one another but disposed in different planes.

In the gear scheme of FIG. 1A, the infinitely variable transmission canoperate in three modes. One of the three clutch assemblies is engagedduring each mode. In one embodiment, for example, the C1 clutch assemblyis engageable in the first mode. In this mode, the transmission outputcan rotate in the reverse and forward direction. The transmission canalso achieve “gear neutral”, meaning there is transmission input speedbut approximately zero transmission output speed.

In a second mode, the C2 clutch assembly is engaged and the transmissionoutput can rotate in the forward direction. Similarly, in a third mode,the C3 clutch assembly is engaged and the transmission output can rotatein the forward direction. In each mode, only one clutch assembly isengaged, and therefore during the transition between operating modes oneclutch assembly is engaged and another clutch assembly is disengaged.

The engaging and releasing of clutch assemblies results in a synchronousshift. The applying and releasing of clutch assemblies can be achievedelectrically, mechanically, hydraulically, or according to other knownmethods. The shifting between modes can be achieved manually by avehicle operator, or alternatively completely or partially automated(e.g., by electronic, electro-hydraulic or electro-pneumatic controlsystems).

Although only clutch assemblies have been described, other torquetransmitting mechanisms can be used such as brakes, wet clutches, dryclutches, and dog clutches. In the described embodiments, the clutchassemblies can include rotating clutches. In some embodiments,friction-based torque transmitting mechanisms can be used, while inother embodiments, interference-based torque transmitting mechanisms canbe used. The clutch assemblies can include pistons, housings, hubs,housings, seals, o-rings, apply and/or return springs, friction plates,reaction plates, backing plates, or any other component for engaging anddisengaging a clutch assembly.

In the illustrated gear scheme of FIGS. 1A and 1B, the infinitelyvariable transmission can operate in three operating modes. However, alarger or smaller number of operating modes can be provided, and alarger or smaller number of clutch assemblies can be used. For example,if more than three operating modes are desired, more than three clutchassemblies can be used, and if fewer than three operating modes aredesired, less than three clutch assemblies can be used. As describedabove, in FIGS. 1A and 1B, the first operating mode (i.e. mode 1)includes a reverse, geared neutral, and forward operating mode, and theother two modes are forward ranges, but this arrangement is notrequired.

In the gear configuration 1000 of FIG. 1A, the input shaft 100 of theinfinitely variable transmission is driven by the vehicle's drive unit.The input shaft 100 is coupled to a first input gearset 102. The outputof the first input gear set 102 can drive a layshaft 103. In turn, thelayshaft 103 is coupled to the first planetary gearset 104. The outputof one of the components of the planetary gearset 104 is coupled to oneside of the variator assembly 114 via a second input gearset 110 and ashaft 116. The output of another component of the planetary gearset 104is coupled to another side of the variator assembly 114 via a thirdinput gearset 112 and a shaft 118. As shown in FIG. 1A, the shaft 116can be coupled to the input side of the variator assembly 114 and theshaft 118 can be coupled to the output side of the variator assembly114. Other arrangements, however, can be incorporated into this design.One such arrangement is achieved by flipping the input side and outputside of the variator assembly 114 so that the shaft 116 is coupled tothe output side of the variator assembly 114 and the shaft 118 iscoupled to the input side of the variator assembly 114.

The second planetary gearset 120 can have a component coupled to oneside of the variator assembly 114 via the second input gearset 110 andanother component coupled to the other side of the variator assembly 114via the third input gearset 112. Also, the output of one component ofthe first planetary gearset 104 can also be coupled to a component ofthe second planetary gearset 120. As such, the output of one componentof the second planetary gearset 120 can be coupled to the C1 clutchassembly and the output shaft 126 via a second output gearset 124.

The gear configuration 1000 of FIG. 1A includes a first output gearset122 and a second output gearset 124. The clutch assemblies C1, C2, andC3 are selectively engageable to determine the torque output by theoutput shaft 126. When either of C1 or C3 clutch assemblies is engaged,the second output gearset 124 is employed. When the C2 clutch assemblyis engaged, then the first output gearset 122 is employed.

One exemplary layout 1100 of the gear configuration 1000 is illustratedin FIG. 1B. As shown, the input shaft 100, output shaft 126, variatorshaft 116, and layshaft 103 are arranged along axes. For example, theinput shaft 100 is disposed along axis 176, the output shaft is disposedalong axis 184, the variator shaft is disposed along axis 174, and thelayshaft is disposed along axis 178. As described above, each of theseaxes are parallel to one another. Axis 176 and axis 184 can be coaxial,but is not required. Axis 174 and axis 178 are not coaxial such that thevariator assembly 114 is positioned adjacent to the first planetarygearset 104 and second planetary gearset 120, both of which are disposedalong axis 178. In one embodiment, the axes 174, 176, 178, and 184 areparallel but not coaxial with one another.

The first input gearset 102 can include a pair of meshing gears 128,130. The first gear 128 can be coupled to the input shaft 100 and thesecond gear 130 can be coupled to the layshaft 103. Thus, torque can betransferred from the input shaft 100 to the layshaft 103 via the firstinput gearset 102.

In the illustrated embodiment of FIG. 1B, the second input gearset 110and third input gearset 112 can each include a gear with an idler or achain and sprocket assembly. The second input gearset 110, for example,can include a first sprocket 134 and a second sprocket 132. A chain 136can be coupled between the first sprocket 134 and second sprocket 132 totransfer torque therebetween. Likewise, the third input gearset 112 caninclude a first sprocket 150, a second sprocket 152, and a chain 154coupled therebetween. Torque can be transferred between the firstsprocket 150 and the second sprocket 152 by the chain 154.

The first output gearset 122 and second output gearset 124 can includemeshing gears. For example, the first output gearset 122 can be formedby a first gear 172 and a second gear 170. The second output gearset 124can be formed by a gear 168 and the second gear 170. The second gear 170can be coupled to the output shaft 126 so that torque can be transferredto the output shaft 126 via the first output gearset 122 and secondoutput gearset 124. In addition to the output gearsets, an idler gearset186 can be included in the layout 1100 of FIG. 1B. Although not shown,the idler gearset 186 can be disposed along axes 174 or 176; or,alternatively, the idler gearset 186 can be arranged on a differentaxis. As shown, the second output gearset 124 includes gears 168, 170,and the idler gearset 186 interposed therebetween.

The first planetary gearset 104 can include a first ring gear 138, afirst carrier assembly 140, and a first sun gear 142. The first carrierassembly 140 can include a plurality of pinion gears (identified also as140 in FIG. 1B) which mesh with the first ring gear 138 and first sungear 142. Similarly, the second planetary gearset 120 can include asecond ring gear 144, a second carrier assembly 146, and a second sungear 148. The second carrier assembly 146 can include a plurality ofpinion gears (identified as 146 in FIG. 1B) which mesh with the secondring gear 144 and second sun gear 148.

Referring again to FIG. 1B, the first ring gear 138 can be coupled orsplined to the layshaft 103. As the layshaft 103 rotates, the first ringgear 138 can rotate at about the same speed. In this configuration, thefirst ring gear 138 is an input component of the first planetary gearset104 and the first carrier assembly 140 and first sun gear 142 are outputcomponents. This is not required, however, as in different embodimentsone or more of the components of the first planetary gearset 104 can beinput and/or output components. For purposes of this disclosure, theterms “input” and “output” are used to describe the flow of powerbetween two or more components at any given time. Due to the nature ofthe infinitely variable transmission, the flow of power through twocomponents can vary depending on the operating condition (e.g., mode).For instance, a component can be an input source in one operating modeand an output source in another operating mode.

The first ring gear 138 can be coupled (e.g., meshed or splined) to thepinion gears of the first carrier assembly 140. The first carrierassembly 140 can be an input or output component of the first planetarygearset. As an output component, the carrier assembly 140 transmitstorque to the second input gearset 110, e.g., the sprocket 134. In otherwords, the carrier assembly 140 can drive the sprocket 134, whichthrough the coupling of the chain 136 to the sprocket 132, torque istransmitted through the second input gearset 110 to the variator shaft116. This is because the sprocket 132 is coupled to the variator shaft116, which as described above, is coupled to the input side of thevariator assembly 114.

The input side of the variator assembly 114 includes a pair of input orend discs 156, 158. Torque can be transferred from the input discs 156,158 to a pair of output discs 160, 162 of the variator assembly 114 viarollers (not shown) and traction fluid (not shown). The output side ofthe variator assembly 114, e.g., output discs 160, 162, are coupled toshaft 118. The shaft 118 is coupled (e.g., splined) to the sprocket 150of the third input gearset 112. The sprocket 150 is an input to sprocket152 via chain 154. Thus, torque can be transferred from shaft 118through the third input gearset 112 via sprockets 150, 152 and chain154.

As shown in FIGS. 1A and 1B, the third input gearset 112 can be coupledto the second output gearset 124 when the C3 clutch assembly is engaged.In particular, the sprocket 152 is coupled (e.g., splined) to shaft 164.Shaft 164 can be a hollow shaft that is also splined to the C3 clutchassembly. When the C3 clutch assembly is engaged, torque can betransferred from the shaft 164 to gear 168 via the C3 clutch assemblyand another shaft (not shown). As described above, gear 168 is coupledto gear 170 through an idler gear 186 to form the second output gearset124. Gear 170 is coupled (e.g., meshes or splined) to output shaft 126to transfer torque to the vehicle's output load (e.g., drive axis).

The first carrier assembly 140 can also transfer torque to the first sungear 142. The first sun gear 142 is coupled to the second sun gear 148of the second planetary gearset 120 via a coupling 106. The coupling 106can include a housing, hub, shaft, spline, etc. The first sun gear 142and second sun gear 148 can also be coupled by additional shafts andother components which are not shown in FIG. 1B. In this embodiment, thesecond sun gear 148 transfers torque to the pinion gears 146. In turn,the second carrier assembly 146 can transmit torque to shaft 166. In thefirst operating mode, when the C1 clutch assembly is engaged, outputtorque transmitted by the second carrier assembly 146 can be transferredthrough the C1 clutch assembly to gear 168 of the second output gearset124. Since gear 168 couples with gear 170 via idler gear 186, torque istransferred to the output shaft 126.

In addition, the first carrier assembly 140 can transfer torque to thesecond ring gear 144 through a coupling 108 (e.g., housing, hub, shaft,spline, etc.). The second ring gear 144, which meshes with the piniongears 146, can therefore transfer torque between the first carrierassembly 140 and second carrier assembly 146. Again, as previouslydescribed, when the C1 clutch assembly is engaged, torque can betransmitted from the second carrier assembly 146 to the output shaft 126via shaft 166 and the second output gearset 124.

To operate in the second operating mode, the C2 clutch assembly isengaged. In FIG. 1B, torque is transferred from the input shaft 100 tothe variator shaft 116 via first input gearset 102, layshaft 103, firstring gear 138, first carrier assembly 140, and second input gearset 110.The variator shaft 116 can be coupled or splined to another shaft (notshown) that is coupled to the C2 clutch assembly. When the C2 clutchassembly is engaged, the variator shaft 116 can transfer torque to gear172 through the C2 clutch assembly. Since gear 172 and gear 170 form thefirst output gearset 122, torque can be transferred through the firstoutput gearset 122 to the output shaft 126.

In FIGS. 2A, 3A, and 4A, gear configurations are illustrated for aninfinitely variable transmission. These gear configurations are similarto gear configuration 1000 shown in FIG. 1. In these gearconfigurations, a naming convention is consistently used between FIGS.1A, 2A, 3A, and 4A. In particular, each component includes a three orfour digit reference number, the first digit corresponding to the Figurenumber and the latter two or three digits referring to the component.For example, the input shaft in FIG. 1B is referred to as 100, and inFIGS. 2A, 3A, and 4A the input shaft is referred to as 200, 300, and400, respectively. Similarly, the output shaft in FIG. 1B is referred toas 126, and in FIGS. 2A, 3A, and 4A the output shaft is referred to as226, 326, and 426.

With reference to the embodiment of FIG. 2B, a layout 2100 of the gearconfiguration 2000 of FIG. 2A is shown. In the layout 2100, theinfinitely variable transmission includes an input shaft 200, outputshaft 226, variator shaft 216, and layshaft 203 arranged along axes. Forexample, the input shaft 200 is disposed along axis 278, the outputshaft 226 is disposed along axis 286, the variator shaft 216 is disposedalong axis 276, and the layshaft 203 is disposed along axis 280. Each ofthese axes is parallel to one another. Axis 278 and axis 286 can becoaxial, but is not required. Axis 276 and axis 280 are not coaxial suchthat the variator assembly 214 is positioned adjacent to the firstplanetary gearset 204 and second planetary gearset 220, both of whichare disposed along axis 280. In one embodiment, the axes 276, 278, 280,and 286 are parallel but not coaxial with one another.

The infinitely variable transmission of FIG. 2B can include three clutchassemblies, i.e., C1, C2, and C3. In an alternative embodiment, thetransmission may also include an input clutch assembly (not shown). Asdescribed above, the infinitely variable transmission can operate inthree operating modes. In the first operating mode, e.g., mode 1, the C1clutch assembly is engaged and the transmission can achieve reverse,gear neutral, or a first forward range. In the second operating mode,e.g., mode 2, the C2 clutch assembly is engaged and the transmission canoperate in a second forward range. In the second forward range, thetransmission output shaft 226 can rotate faster than in the firstforward range. Thus, the vehicle is able to achieve a greater vehiclespeed. In the third operating mode, e.g., mode 3, the C3 clutch assemblyis engaged and the transmission can operate in a third forward range. Inthe third forward range, the transmission output shaft 226 can rotatefaster than in the first and second forward ranges.

The layout 2100 of FIG. 2B is substantially the same as the layout 1100of FIG. 1B, except for the location of the C1 clutch assembly relativeto the C3 clutch assembly. In FIG. 2B, the C1 clutch assembly ispositioned behind the C3 clutch assembly. The torque paths through theinfinitely variable transmission, however, are still substantially thesame as in the layout 1100 of FIG. 1B.

In mode 1, for example, the C1 clutch assembly is engaged. To operate inthis mode, torque passes through the input shaft 200 and layshaft 203via the first input gearset 202. In particular, the input shaft 200 canbe coupled to a vehicle's drive unit and transmit torque to the firstinput gearset 202. The first input gearset can include a first gear 228and a second gear 230 that mesh with one another. The second gear 230 isconcentrically coupled or splined to the layshaft 203. Similarly, thefirst gear 228 can be concentrically coupled or splined to the inputshaft 200.

A first ring gear 238 of a first planetary gearset 204 can be coupled orsplined to the layshaft 203 and thereby transfer torque to a firstcarrier assembly 240. Similar to the first carrier assembly 140 of FIG.1B, the first carrier assembly 240 can transfer torque to a second ringgear 244 of a second planetary gearset 220. The first carrier assembly240 can be coupled or splined via a shaft 206 or other coupling to thesecond ring gear 244. The second ring gear 244 is input to the secondplanetary gearset 220 and torque passes therethrough to a second carrierassembly 246. In turn, the second carrier assembly 246 is coupled to theC1 clutch assembly via a shaft 266 or other coupling. When the C1 clutchassembly is engaged, torque passes to a gear 268 of a second outputgearset 224. The second output gearset 224 includes gears 268, 272 andan idler gearset 274 interposed therebetween. Gear 272 is concentricwith the output shaft 226 and therefore output torque is transferred tothe output shaft 226 to power a vehicle's load (e.g., drive axis).

In mode 2, the C2 clutch assembly is engaged. As such, torque istransferred through the input shaft 200, first input gearset 202, andfirst ring gear 238 to the first carrier assembly 240. The first carrierassembly 240 can be coupled to a second input gearset 210. Similar tothe first input gearset 110 of FIG. 1B, the first input gearset 210 ofFIG. 2B includes a chain and sprocket assembly. An input sprocket 234 iscoupled to the first carrier assembly 240 and torque is transferredthrough chain 236 to output sprocket 232. Output sprocket 232 is coupledor splined to the variator shaft 216. The variator shaft 216 can becoupled or splined with one or more shafts (not shown) so that torque istransferred from the variator shaft to the C2 clutch assembly. As shownin FIG. 2A, when the C2 clutch assembly is engaged, the variator shaft216 is coupled to a first output gearset 222. The first output gearsetcan include two meshing gears 270, 272. Gear 272 can be coupled orsplined with the output shaft 226, and therefore torque can betransferred from the variator shaft 216 to the output shaft 226 via theC2 clutch assembly and the first output gearset 222.

In the third operating mode, e.g., mode 3, the C3 clutch assembly isengaged. In this mode, torque can be transferred along three differentpaths. First, the first carrier assembly 240 is coupled (e.g., splinedor meshes) to the first sun gear 242. As shown in FIG. 2A, when the C3clutch assembly is engaged, torque can pass from the first planetarygearset 204 to the second output gearset 224 via a coupling 208 (e.g.,housing, hub, shaft, spline, etc.). As described above, the secondoutput gearset 224 includes gears 268, 272 (with the idler gear 274interposed therebetween) and gear 272 is coupled or splined to theoutput shaft 226.

Second, the first carrier assembly 240 is also coupled to the secondring gear 244 of the second planetary gearset 220. The second ring gear244 can transfer torque to the second carrier assembly 246, which inturn can transfer torque to a second sun gear 248. When the C3 clutchassembly is engaged, the second sun gear 248 can transfer torque to thesecond output gearset 224 via a shaft 264 or other coupling. The secondoutput gearset 224 is coupled or splined to the output shaft 226 toprovide torque to the vehicle's output load.

In a third path, the first carrier assembly 240 can transfer torque tothe variator shaft 216 via the second input gearset 210 (e.g., chain andsprocket assembly). The input side of the variator assembly 214 iscoupled or splined to the variator shaft 216. In particular, input discs256, 258 (or end discs) are coupled to the input side of the variatorassembly 214 and output discs 260, 262 (or center discs) are coupled tothe output side thereof. A plurality of rollers and traction fluidassist with transferring torque from the input discs 256, 258 to theoutput discs 260, 262.

The output discs 260, 262 of the variator assembly 214 are coupled orsplined to a shaft 218, which is coupled or splined with a third inputgearset 212. In FIG. 2B, the third input gearset 212 can include a chainand sprocket assembly. For example, torque transmitted to the shaft 218can be further transferred from an input sprocket 250 to an outputsprocket 252 via chain 254. The output sprocket 252 can transfer torqueto the second output gearset 224 when the C3 clutch assembly is engaged.In particular, the output sprocket 252 can be coupled to the gear 268via the shaft 264 or other coupling. As torque is transferred to thesecond output gearset 224, the output shaft 226 can further transmit thetorque to the vehicle's output load.

Referring to FIG. 2B, the length of the infinitely variable transmissioncan be measured from the front end of an input flange 282 to the rearedge of an output shaft 226. The input flange 282 can be coupled to thevehicle's drive unit (e.g., engine). As described above, with thedifferent shafts being positioned on parallel, but non-coaxial axes orcenterlines, the overall length of the transmission can be reduced. Inthis compact configuration, the infinitely variable transmission canadvantageously be incorporated into a rear-end bus application.

A different layout 3100 of the gear configuration 3000 is shown in FIG.3B. In the layout 3100, the infinitely variable transmission has threeclutch assemblies, i.e., C1, C2, and C3, each of which is engaged inmode 1, mode 2, and mode 3, respectively. Similar to the layout 2100 ofFIG. 2B, in the layout 3100 of FIG. 3B the C1 clutch assembly ispositioned behind or closer to the rear of the transmission than the C3clutch assembly. As described above, the gear configuration 3000 shownin FIG. 3A is similar to the gear configurations 1000, 2000 of FIGS. 1Aand 2A, respectively.

In the layout of FIG. 3B, an input shaft 300 is coupled to a layshaft303 via a first input gearset 302. The first input gearset 302 includestwo meshing gears 328, 330. The layshaft 303 can be coupled to differentcomponents of a first planetary gearset 304 and a second planetarygearset 320. As shown, for example, the layshaft 303 can be coupled to afirst ring gear 338 and first carrier assembly 340 of the firstplanetary gearset 304 and a second ring gear 344 and second carrierassembly 346 of the second planetary gearset 320. Torque can betransferred from the first ring gear 338 to the first carrier assembly340 and from the second ring gear 344 to the second carrier assembly346. Also, the first carrier assembly 340 can transfer torque to a firstsun gear 342 or a second input gearset 310 via a coupling 306 (e.g.,housing, hub, shaft, spline, etc.). On the other hand, the secondcarrier assembly 346 can transfer torque to a second sun gear 348.

The second input gearset 310 and a third input gearset 312 include chainand sprocket assemblies. In the second input gearset 310, for example,torque is received by an input sprocket 334 and transferred to an outputsprocket 332 via a chain 336. Likewise, in the third input gearset 312,torque is received by an input sprocket 350 and transferred to an outputsprocket 352 via a chain 354.

In the illustrated layout 3100, a variator assembly 314 is positionedadjacent to the first planetary assembly 304 and the second planetaryassembly 320. The variator assembly 314 can include an input side and anoutput side. The input side includes a pair of input discs 356, 358(e.g., end discs) and the output side includes a pair of output discs360, 362 (e.g., center discs). A plurality of rollers (not shown) andtraction fluid (not shown) transfer torque from the input discs 356, 358to the output discs 360, 362. The input discs 356, 358 can be coupled toa variator shaft 316, whereas the output discs 360, 362 can be coupledto a different shaft 318. As shown, the second input gearset 310 iscoupled to the variator shaft 316 and the third input gearset 312 iscoupled to the other shaft 318.

This embodiment also includes a first output gearset 322 and a secondoutput gearset 324. The first output gearset 322 includes a pair ofmeshing gears 368, 372 and the second output gearset 324 includes a pairof gears 370, 372 with an idler gear 386 being interposed therebetween.

As described above, the infinitely variable transmission can operate inthree modes. In a first mode, the C1 clutch assembly is engaged. Torquecan be transferred from the second carrier assembly 346, for example, tothe second output gearset 324 via shaft 366 and/or other couplings whenthe C1 clutch assembly is engaged. The gear 370 can be coupled to thesecond carrier assembly 346 when the C1 clutch assembly is engaged, andtorque thereby can be transferred to the output shaft 326 via gear 372.

Also, or alternatively, torque can be transferred from the first ringgear 338 to gear 370 via first carrier assembly 340. Torque can also betransferred from the input shaft 300 to the second output gearset 324via the first planetary gearset 304 and second planetary gearset 320. Inthis embodiment, torque is transferred through the first ring gear 338,the first carrier assembly 340, the first sun gear 342, the second sungear 348, and the second carrier assembly 346. Torque can also betransferred from the second sun gear 348 to the second ring gear 344 viathe second carrier assembly 346.

In mode 2, the C2 clutch assembly is engaged. Torque can be transferredthrough the chain and sprocket assembly of the second input gearset 310.Torque can further be transferred from the second sprocket 332 to thevariator shaft 316. When the C2 clutch assembly is engaged, torque canbe transferred to the first output gearset 322 via gear 368. Since gear368 meshes with gear 372, which is coupled or splined to the outputshaft 326, torque can be transferred to the output shaft 326 of thetransmission.

In mode 3, the C3 clutch assembly is engaged. Torque can be transferredthrough the variator assembly 314 and to shaft 318. Since shaft 318 iscoupled or splined with sprocket 350 of the third input gearset 312,torque can be transferred through to shaft 364 or other coupling viasprockets 350, 352 and chain 354. When the C3 clutch assembly isengaged, torque can be transferred to gear 370 of the second outputgearset 324. The idler gear 386 can transfer from torque from gear 370to gear 372, and thus torque can be transferred to the output shaft 326of the transmission.

In addition, when the C3 clutch assembly is engaged, torque can also betransferred from the first sun gear 342 to gear 370 via a coupling 308(e.g., housing, hub, shaft, spline, etc.) and/or several shafts (e.g.,shaft 364) or other couplings. As described above, with the gear 370coupled to the gear 372 via idler gear 386, torque can be transferred tothe output shaft 326 of the transmission. There can be other torquepaths (e.g., via the second planetary gearset 320) in the layout 3100 ofFIG. 3B such that, when the C3 clutch assembly is engaged, torque can betransmitted to the vehicle's output load.

As shown in FIG. 3B, the input shaft 300 and output shaft 326 arepositioned on different axes. The input shaft 300 is disposed along axis376 and the output shaft 326 is disposed along axis 384. Axis 376 can beparallel to and coaxial with axis 384, but this is not required. Forexample, axis 376 can be parallel but non-coaxial with axis 384. Inanother embodiment, axis 376 and axis 384 can be non-parallel to oneanother.

The variator shaft 316 can be disposed along axis 374 and the layshaft303 can be positioned along axis 378. Axes 374 and 378 can be parallelto one another, but in order to reduce the length of the infinitelyvariable transmission, the two axes are non-coaxial. As such, thevariator assembly 314, which is positioned on axis 374, is positionedadjacent to the planetary gearsets 304, 320, which are disposed alongaxis 378. In other words, a more compact packaging size can be achievedby positioning the variator assembly 314 on a different axis than theplanetary gearsets. As shown in FIG. 3B, two of the three clutchassemblies (C1 and C3) can be positioned along axis 378 with theplanetary gearsets, and the other clutch assembly (C2) can be positionedalong axis 374 with the variator assembly 314. In this layout, thevariator shaft 316 and its corresponding axis 374 and the layshaft 303and its corresponding axis 378 form countershafts to the output shaft326 and its corresponding axis 384.

The illustrated embodiment of FIG. 3B, like the previously describedembodiments, is advantageous over the gear configurations and packagingof conventional infinitely variable transmissions due to the fourdifferent axes (e.g., 374, 376, 378, and 384) upon which components canbe positioned. The overall length of the infinitely variabletransmission, which can be measured from the front edge of an inputflange 380 to the rear-most edge of the output shaft 326 in FIG. 3B, cantherefore be reduced.

With reference to FIG. 4B, a different embodiment of a gearing layout4100 is illustrated. The layout 4100 is similar to the layout 1100 ofFIG. 1B, except for a second idler gear and a different gearing schemefor two of the three input gearsets. In one aspect, the gearing layout4100 can also include an input clutch assembly (not shown) in additionto the three clutch assemblies, i.e., C1, C2, and C3. The infinitelyvariable transmission includes four different axes or centerlines. Aninput shaft 400 is positioned on a first axis 480 and an output shaft426 is positioned on a second axis 488. The first axis 480 and secondaxis 488 can be parallel to one another. In one embodiment, the two axes480, 488 are parallel and coaxial with one another, but in analternative embodiment the two axes 480, 488 are parallel andnon-coaxial with one another.

A third axis 478 can include a variator assembly 414, variator shaft416, and one of the three clutch assemblies (i.e., the C2 clutchassembly). A fourth axis 482 can include a layshaft 403, a pair ofplanetary gearsets 404, 420, and the other two clutch assemblies (i.e.,the C1 clutch assembly and the C3 clutch assembly). The third axis 478and fourth axis 482 can be parallel to one another, but the two axes arenot coaxial. In this arrangement, the variator assembly 414 can bepositioned adjacent to the planetary gearsets, not on a different axisor centerline, so that the overall length of the infinitely variabletransmission is less than conventional infinitely variabletransmissions. In one embodiment, the first axis 480, second axis 488,third axis 478, and fourth axis 482 can be parallel to one another, butno two axes are coaxial. In another embodiment, at least two of the fouraxes can be coaxial. Similar to the previously described embodiments,the overall length of the infinitely variable transmission can bemeasured from the front edge of an input flange 484 (defined by thedashed line) to the rear-most edge of the output shaft 426.

As described above, the layout 4100 of FIG. 4B is similar to the layout1100 of FIG. 1B. The input shaft 400 can be coupled to a first inputgearset 402, which is formed of two meshing gears 428, 430. Gear 428 canbe coupled or splined to the input shaft 400 such that the input shaft400 and gear 428 are concentric with one another. Likewise, gear 430 canbe coupled or splined to the layshaft 403 such that the layshaft 403 andgear 430 are concentric with one another.

The layshaft 403 can be coupled to a first planetary gearset 404, inparticular, to a first ring gear 438 of the first planetary gearset 404.As the layshaft 403 rotates about its axis 482, the first ring gear 438can rotate at substantially the same speed. The first ring gear 438meshes with pinion gears of a first carrier assembly 440, and the piniongears further mesh with a first sun gear 442. The first carrier assembly440 and first sun gear 442 can transfer output torque to variouscomponents including a second output gearset 410 and a second planetarygearset 420. For example, the first carrier assembly 440 can transfertorque to a second ring gear 444 of the second planetary gearset 420 viaa coupling 408 (e.g., housing, hub, shaft, spline, etc.). Like the firstring gear 438, the second ring gear 444 meshes with pinion gears of asecond carrier assembly 446. The pinion gears of the second carrierassembly 446 also mesh with a second sun gear 448.

The first carrier assembly 440 can also couple to the second inputgearset 410 via a shaft or other coupling. Unlike the second inputgearset 110 of FIG. 1B, the second input gearset 410 of FIG. 4B does notinclude a chain and sprocket assembly. Instead, the second input gearset410 comprises two meshing gears 432, 434. Torque can be transferred fromthe first carrier assembly 440 to gear 432 via gear 434. Gear 432 can becoupled or splined to the variator shaft 416, so torque transferred togear 432 is in turn transferred to the variator shaft 416.

The variator shaft 416 is coupled to an input side of the variatorassembly 414. The input side of the variator assembly 414 includes apair of input discs 456, 458, also referred to as end discs. The inputdiscs 456, 458 can transfer torque to a pair of output discs 460, 462(i.e., center discs) via a plurality of rollers (not shown) and tractionfluid (not shown). The output discs 460, 462 can be coupled to a shaft418 and transfer torque to the third input gearset 412. Like the secondinput gearset 410, the third input gearset 412 includes a pair ofmeshing gears 450, 452. Gear 450 transfers torque to gear 452, which iscoupled or splined to the C3 clutch assembly via shaft 464 or othercoupling.

In the layout of FIG. 4B, there are two output gearsets 422, 424. Thefirst output gearset 422 includes a pair of gears 468, 472 coupledtogether via a first idler gearset 474 interposed therebetween. Gear 468can be coupled or splined to one or more shafts including the variatorshaft 416 along the axis 478. Gear 472 can be coupled or splined to theoutput shaft 426 such that torque can be transferred through the firstoutput gearset 422 to the output shaft 426. The second output gearset424 also includes two gears 470, 472 coupled to one another via a secondidler gearset 476 interposed therebetween. Since the gear 472 is coupledor splined to the output shaft 426, torque can be transferred from thegear 470 to the output shaft 426 via gear 472 and idler gear 476.

In modes 1, 2, and 3, torque is transferred from the input shaft 400 tothe output shaft 426 along similar paths as described above withreference to FIG. 1B. In particular, in mode 1 when the C1 clutchassembly is engaged, torque can be transferred from the input shaft 400to the output shaft 426 via the first input gearset 402, layshaft 403,first ring gear 438, first carrier assembly 440, coupling 408, secondring gear 444, second carrier assembly 446, shaft 466, C1 clutchassembly, and second output gearset 424. In mode 2, when the C2 clutchassembly is engaged, torque can be transferred from the input shaft 400to the output shaft 426 via the first input gearset 402, the layshaft403, the first ring gear 438, the first carrier assembly 440, the secondinput gearset 410, the variator shaft 416, the C2 clutch assembly, andthe first output gearset 422.

In the third operating mode, i.e., when the C3 clutch assembly isengaged, torque can be transferred through several torque paths from theinput shaft 400 to the output shaft 426. First, torque can betransferred from the input shaft 400 to the output shaft 426 via thefirst input gearset 402, the layshaft 403, the first ring gear 438, thefirst carrier assembly 440, the second input gearset 410, the variatorshaft 416, the variator assembly 414, shaft 418, the third input gearset412, the shaft 464, the C3 clutch assembly, and the second outputgearset 424. Also, torque can be transferred from the input shaft 400 tothe output shaft 426 via the first input gearset 402, the layshaft 403,the first ring gear 438, the first carrier assembly 440, the first sungear 442, the coupling 406 (e.g., housing, hub, shaft, spline, etc.),shaft 464, the C3 clutch assembly, and the second output gearset 424.Torque can further be transferred through the first carrier assembly440, the coupling 408 (e.g., housing, hub, shaft, spline, etc.), thesecond ring gear 444, the second carrier assembly 446, the second sungear 448, shaft 464, the C3 clutch assembly, and the second outputgearset 424.

In FIGS. 1A, 2A, 3A, and 4A, gear configurations or schemes are shownfor a three-mode infinitely variable transmission described above. Ineach of these gear schemes, a double shunt architecture is used for thefirst operating mode. In other words, the variator assembly 114 (FIG.1A) is not directly coupled to either the first planetary assembly 104or the second planetary assembly 120. Instead, there are two shunt pathsand the gear neutral mode can be achieved since the second planetary 120is coupled to the output shaft 126.

Also, in each of these gear schemes, an output coupled shunt is achievedin the second and third operating modes. In the output coupled shunt, asplit power pass is achieved because the first ring gear 138, firstcarrier assembly 140, and first sun gear 142 are rotating at differentspeeds with different torque ratios (FIG. 1A). As such, at least aportion of the torque passing through the infinitely variabletransmission passes through the variator assembly 114.

With reference to the embodiments of FIGS. 5 and 6, a front view of agearing configuration for an infinitely variable transmission is shown.In FIG. 5, for example, the packaging of the internal components can bepositioned along at least four different axes or centerlines. In thisembodiment, an input shaft can be positioned along a first axis 500 orcenterline. An output shaft can be positioned along a second axis 502 orcenterline. As shown, the first axis 500 and second axis 502 areparallel to one another, but the two axes are not coaxial. Instead, thesecond axis 502 is vertically spaced from the first axis 500. In adifferent embodiment, the first axis 500 and second axis 502 can beparallel and coaxial.

A variator can be positioned on a third axis 504 or centerline. Thethird axis 504, upon which one of three clutch assemblies can bepositioned, is parallel to the first axis 500 and second axis 502.However, the third axis 504 is spaced from the two axes 500, 502 and ispositioned near the passenger side 510 of the vehicle. As such, for asubstantially vertical plane passing through the first axis 500 and thesecond axis 502, the third axis 504 is positioned outside the plane.

A pair of planetary gearsets and two clutch assemblies can be disposedalong a fourth axis 506 or centerline. A layshaft can also be positionedalong the fourth axis 506. The fourth axis 506 can be parallel to thefirst axis 500, the second axis 502, and the third axis 504. As shown,however, the fourth axis 506 is not coaxial with the other three axes.Instead, the fourth axis 506 is positioned near the driver side 512 ofthe vehicle. In this arrangement, the variator and planetary gearsetsare adjacent to one another, but are not on the same axis or centerline.As described above, this enables the internal components of theinfinitely variable transmission to be more compactly packaged andthereby reduces the overall length of the transmission.

As also shown in FIG. 5, an idler gearset can be positioned along afifth axis 508 or centerline. The fifth axis 508 can be parallel to theother axes, but as shown, the fifth axis 508 is not coaxial with theseother axes. In an alternative embodiment, the first axis 508 can becoaxial with the first axis 500 and third axis 504.

Referring to FIG. 6, the different components are shown positioned alongeach corresponding axis. For example, in FIG. 1B, the first inputgearset 102 includes two meshing gears 128, 130. Gear 128, whichcorresponds to gear 600 in FIG. 6, is positioned along the first axis500 (i.e., axis 176 of FIG. 1B). Gear 130, which corresponds to gear 602in FIG. 6, is positioned along the fourth axis 506 (i.e., axis 178 ofFIG. 1B). Also, the second input gearset 110 of FIG. 1B includes a firstsprocket 134 coupled to a second sprocket 132 via a chain 136. In FIG.6, the first sprocket 134 is identified as 604 and the second sprocketis identified as 606. The first sprocket 604 is coupled to the secondsprocket 606 by a chain 608.

As shown, the second sprocket 606 is positioned along the variatorshaft, i.e., the third axis 504 (i.e., axis 174 of FIG. 1B). Asdescribed above, torque can be transferred from the variator to a thirdinput gearset (i.e., gearset 112 of FIG. 1B). The third input gearsetincludes a first sprocket 610 coupled to a second sprocket 612 via achain 614. The second sprocket 612, which corresponds to sprocket 152 ofFIG. 1B, is positioned along the fourth axis 506 or centerline.

As illustrated in FIG. 1B, there can be two output gearsets 122, 124.The first output gearset 122 includes a pair of meshing gears (e.g.,gears 170, 172) and the second output gearset 124 includes a pair ofgears 168, 170 with an idler gear 186 interposed therebetween. Outputgear 170, which is included in both output gearsets, can be coupled orsplined to the output shaft and thus is concentric or disposed along thesecond axis 502 (i.e., axis 184 of FIG. 1B). In FIG. 6, the output gear170 is identified as output gear 622. Gear 172 of the first outputgearset 122 is disposed along the same axis or centerline as thevariator, i.e., the third axis 504. This gear is identified as inputgear 616. Gear 168 of the second output gearset is positioned along thesame axis or centerline as the layshaft 103 (as shown in FIG. 1B), whichis the fourth axis 506 shown in FIG. 6. This gear 168 is identified asan input gear 618 in FIG. 6. As also shown in FIG. 6, an idler gear 620(identified as idler gear 186 in FIG. 1B) is disposed along the fifthaxis 508 or centerline and meshes or splines with the input gear 618 andoutput gear 622.

In other embodiments, there can be additional axes or centerlines.Components can be arranged differently and positioned on different axesor centerlines. There can also be additional or fewer componentsdepending on the application and intended use. For instance, any one ofthe above-described embodiments can include an input clutch assembly.

A different embodiment of a gear configuration and corresponding layoutof an infinitely variable transmission is illustrated in FIGS. 7A and7B, respectively. The layout 7100 is similar to the gearing layout 4100of FIG. 4B, except for the inclusion of an input coupler 701 in theembodiment of FIGS. 7A and 7B. The input coupler 701 can be a standardclutch assembly similar to the three clutch assemblies, C1, C2, and C3.The input coupler can be a dry clutch assembly, a damper assembly, astand alone clutch assembly (e.g., a rotating clutch assembly), a spragor roller clutch assembly or any combination thereof. As shown in FIG.7B, the input coupler can be disposed along an input centerline or axis780 and be coupled to an input shaft 700.

Similar to the illustrated embodiment of FIG. 4B, the layout 7100 of theinfinitely variable transmission can include four different axes orcenterlines. The input coupler 701 and input shaft 700 is positioned onthe first axis 780 and an output shaft 726 is positioned on a secondaxis 788. The first axis 780 and second axis 788 can be parallel to oneanother. In one embodiment, the two axes 780, 788 are parallel andcoaxial with one another, but in an alternative embodiment the two axes780, 788 are parallel and non-coaxial with one another.

A third axis 778 can include a variator assembly 714, variator shaft716, and one of the three clutch assemblies (i.e., the C2 clutchassembly). A fourth axis 782 can include a layshaft 703, a pair ofplanetary gearsets 704, 720, and the other two clutch assemblies (i.e.,the C1 clutch assembly and the C3 clutch assembly). The third axis 778and fourth axis 782 can be parallel to one another, but the two axes arenot coaxial. In this arrangement, the variator assembly 714 can bepositioned adjacent to the planetary gearsets, not on a different axisor centerline, so that the overall length of the infinitely variabletransmission is less than conventional infinitely variabletransmissions. In one embodiment, the first axis 780, second axis 788,third axis 778, and fourth axis 782 can be parallel to one another, butno two axes are coaxial. In another embodiment, at least two of the fouraxes can be coaxial.

In this embodiment, the input coupler 701 is disposed on the first axis780 and coupled to the input shaft 700. Referring to FIG. 7A, the inputcoupler can selectively transfer energy from a power source, PS, to thetransmission. The power source, such as an engine or motor, providespower to drive the transmission. However, as described above, in thecase of a diesel engine, the power source can cause damage to thevariator assembly 714 during shutdown. Thus, to avoid possible damage tothe variator assembly 714, the input coupler 701 can selectively couplea power source output, PSO, with the input shaft 700. The power sourceoutput can be a shaft, flywheel, etc.

During operation, the input coupler 701 can be engaged to facilitate thetransfer of energy from the power source, PS, to the input shaft 700. Itis also possible to disengage the input coupler 701 to prevent thetransfer of energy to the input shaft 700. In this way, the variatorassembly 714 is protected from a sudden kick back by the power source.In addition, during startup, the input coupler 701 can be disengaged toprevent torsional vibrations from being transmitted through thetransmission. Accordingly, the infinitely variable transmission is setupsimilar to a conventional manual or automatic transmission duringinitial startup.

The input shaft 700 can be coupled to a first input gearset 702, whichis formed of two meshing gears 728, 730. Gear 728 can be coupled orsplined to the input shaft 700 such that the input shaft 700 and gear728 are concentric with one another. Likewise, gear 730 can be coupledor splined to the layshaft 703 such that the layshaft 703 and gear 730are concentric with one another.

The layshaft 703 can be coupled to a first planetary gearset 704, inparticular, to a first ring gear 738 of the first planetary gearset 704.As the layshaft 703 rotates about its axis 782, the first ring gear 738can rotate at substantially the same speed. The first ring gear 738meshes with pinion gears of a first carrier assembly 740, and the piniongears further mesh with a first sun gear 742. The first carrier assembly740 and first sun gear 742 can transfer output torque to variouscomponents including a second output gearset 710 and a second planetarygearset 720. For example, the first carrier assembly 740 can transfertorque to a second ring gear 744 of the second planetary gearset 720 viaa coupling 708 (e.g., housing, hub, shaft, spline, etc.). Like the firstring gear 738, the second ring gear 744 meshes with pinion gears of asecond carrier assembly 746. The pinion gears of the second carrierassembly 746 also mesh with a second sun gear 748.

The first carrier assembly 740 can also couple to the second inputgearset 710 via a shaft or other coupling. The second input gearset 710comprises two meshing gears 732, 734. Torque can be transferred from thefirst carrier assembly 740 to gear 732 via gear 734. Gear 732 can becoupled or splined to the variator shaft 716, so torque transferred togear 732 is in turn transferred to the variator shaft 716.

The variator shaft 716 is coupled to an input side of the variatorassembly 714. The input side of the variator assembly 714 includes apair of input discs 756, 758, also referred to as end discs. The inputdiscs 756, 758 can transfer torque to a pair of output discs 760, 762(i.e., center discs) via a plurality of rollers (not shown) and tractionfluid (not shown). The output discs 760, 762 can be coupled to a shaft718 and transfer torque to the third input gearset 712. Like the secondinput gearset 710, the third input gearset 712 includes a pair ofmeshing gears 750, 752. Gear 750 transfers torque to gear 752, which iscoupled or splined to the C3 clutch assembly via shaft 764 or othercoupling.

In the layout of FIG. 7B, there are two output gearsets 722, 724. Thefirst output gearset 722 includes a pair of meshing gears 768, 772. Inan alternative embodiment, the two gears 768, 772 can be coupledtogether via a first idler gearset (not shown) interposed therebetween.Gear 768 can be coupled or splined to one or more shafts including thevariator shaft 716 along the axis 778. Gear 772 can be coupled orsplined to the output shaft 726 such that torque can be transferredthrough the first output gearset 722 to the output shaft 726. The secondoutput gearset 724 also includes two gears 770, 772 coupled to oneanother via a second idler gearset 776 interposed therebetween. Sincethe gear 772 is coupled or splined to the output shaft 726, torque canbe transferred from the gear 770 to the output shaft 726 via gear 772and idler gear 776.

In modes 1, 2, and 3, torque is transferred from the input shaft 700 tothe output shaft 726 along similar paths as described above withreference to FIG. 4B. In particular, in mode 1 when the C1 clutchassembly is engaged, torque can be transferred from the input shaft 700to the output shaft 726 via the first input gearset 702, layshaft 703,first ring gear 738, first carrier assembly 740, coupling 708, secondring gear 744, second carrier assembly 746, shaft 766, C1 clutchassembly, and second output gearset 724. In mode 2, when the C2 clutchassembly is engaged, torque can be transferred from the input shaft 700to the output shaft 726 via the first input gearset 702, the layshaft703, the first ring gear 738, the first carrier assembly 740, the secondinput gearset 710, the variator shaft 716, the C2 clutch assembly, andthe first output gearset 722.

In the third operating mode, i.e., when the C3 clutch assembly isengaged, torque can be transferred through several torque paths from theinput shaft 700 to the output shaft 726. First, torque can betransferred from the input shaft 700 to the output shaft 726 via thefirst input gearset 702, the layshaft 703, the first ring gear 738, thefirst carrier assembly 740, the second input gearset 710, the variatorshaft 716, the variator assembly 714, shaft 718, the third input gearset712, the shaft 764, the C3 clutch assembly, and the second outputgearset 724. Also, torque can be transferred from the input shaft 700 tothe output shaft 726 via the first input gearset 702, the layshaft 703,the first ring gear 738, the first carrier assembly 740, the first sungear 742, the coupling 706 (e.g., housing, hub, shaft, spline, etc.),shaft 764, the C3 clutch assembly, and the second output gearset 724.Torque can further be transferred through the first carrier assembly740, the coupling 708 (e.g., housing, hub, shaft, spline, etc.), thesecond ring gear 744, the second carrier assembly 746, the second sungear 748, shaft 764, the C3 clutch assembly, and the second outputgearset 724.

In FIGS. 8A and 8B, an alternative embodiment is shown of a gearingconfiguration and corresponding layout of an infinitely variabletransmission. One difference between the illustrated embodiment of FIGS.8A and 8B compared to the illustrated embodiment of FIGS. 7A and 7B isthe location of the input coupler. In FIG. 7A, for example, the inputcoupler 701 is coupled to the input shaft 700 and disposed between thepower source, PS, and input shaft 700. In FIG. 8A, however, a differentinput coupler 801 is coupled to a variator shaft 816. The input coupler801 can be a damper, for example, or a clutch assembly similar to theC1, C2, and C3 clutch assemblies. In this manner, if the input coupler801 is the same type of clutch assembly as C1, C2, or C3, it can becheaper to design and manufacture since the same type of clutch assemblyis being used. Alternatively, the input coupler 801 can be a dry clutchassembly, a stand alone clutch assembly such as a rotating clutch, asprag or roller clutch assembly or any combination thereof.

In the embodiment of FIGS. 8A and 8B, the input coupler 801 is coupledto an input of the variator assembly 814. The variator assembly 814 caninclude a pair of input discs 856, 858 and a pair of output discs 860,862. In this configuration, the input coupler 801 can be coupled,directly or indirectly, to the input discs 856, 858 and transfer energythereto. As such, the input coupler 801 can selectively transfer energyfrom a power source, e.g., engine, motor, etc., to the variator assembly814. Of course, in this configuration, energy can already be transferredto an input shaft 800 of the transmission, but the input coupler 801 isadvantageously positioned to prevent damage to the variator assemblyduring startup.

Since the gearing configuration and layout of FIGS. 8A and 8B,respectively, are similar to that of FIGS. 7A and 7B, particularly withrespect to the other components (e.g., shafts, axes, gearsets, etc.),this embodiment will not be further described. The reference numbercorresponding to each component in FIGS. 8A and 8B is identical to thesame component in FIGS. 7A and 7B except for the first number in therespective reference number begins with an ‘8’ instead of a ‘7’. Theinfinitely variable transmission of FIGS. 8A and 8B can operate in threemodes, similar to that described above, and may include various axes orcenterlines.

In an alternative embodiment, an input coupler can also be coupled tothe layshaft 703 and therefore be disposed along a layshaft centerlineor axis (i.e., similar to the fourth axis 882). In this arrangement, theinput coupler is still positioned between the vehicle's power source andvariator assembly so that energy transferred through the transmissioncan be selectively transferred to the variator assembly. Similar to theembodiments described above, the input coupler can be selectivelyengaged or disengaged to allow or prevent the transfer of energy to thevariator assembly.

While exemplary embodiments incorporating the principles of the presentinvention have been disclosed hereinabove, the present invention is notlimited to the disclosed embodiments. Instead, this application isintended to cover any variations, uses, or adaptations of the inventionusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this invention pertains andwhich fall within the limits of the appended claims.

What is claimed is:
 1. A method of selectively transferring energy froma power source to an infinitely variable transmission, the methodcomprising: providing an input shaft spaced from an output shaft, atoroidal variator coupled between the input shaft and output shaft, thevariator including a first input disc, a second input disc, a firstoutput disc, and a second output disc, wherein the first and secondinput discs are directly coupled to and rotate integrally with an inputvariator shaft and the first and second output discs are directlycoupled to and rotate integrally with an output variator shaft;providing a first, second, and third clutch assembly coupled between theinput shaft and the output shaft, the second clutch assembly beingcoupled directly to and rotatable integrally with the input variatorshaft and to the first and second input discs, a first planetary gearsetdirectly coupled to the input variator shaft and a second planetarygearset directly coupled to the output variator shaft, and an inputcoupler disposed between the power source and the toroidal variator;rotating the power source in an input direction; transmitting energyfrom the power source to the input shaft; engaging the input coupler toselectively connect the power source to the input shaft; selectivelytransferring energy from the power source to the transmission; engagingthe first clutch assembly and disengaging the second and third clutchassemblies in a first operating mode; and selectively rotating theoutput shaft by the power source in a forward direction, a gear neutral,or a reverse direction while in the first operating mode withoutdisengaging the first clutch assembly and the input coupler.
 2. Themethod of claim 1, wherein the engaging the input coupler comprisesengaging a clutch or a damper.
 3. The method of claim 1, furthercomprising disengaging the input coupler if the power source rotates ina direction opposite the input direction.
 4. The method of claim 1,further comprising selectively coupling the variator to the powersource.
 5. The method of claim 1, further comprising engaging the secondclutch assembly and disengaging the first and third clutch assemblies ina second operating mode.
 6. The method of claim 5, further comprisingselectively rotating the output shaft in a forward direction at a higherrotational speed in the second operating mode than in the firstoperating mode.
 7. The method of claim 6, further comprising selectivelyrotating the output shaft in a forward direction at a higher rotationalspeed in a third operating mode than in the first operating mode andsecond operating mode.
 8. The method of claim 1, further comprisingengaging the third clutch assembly and disengaging the first and secondclutch assemblies in a third operating mode.
 9. The method of claim 1,further comprising selectively rotating the output shaft by the powersource in only a forward direction when the second clutch assembly isengaged.
 10. The method of claim 1, further comprising selectivelyrotating the output shaft by the power source in only a forwarddirection when the third clutch assembly is engaged.